Spaceflight Insider

4th X-37B mission ends with first landing at Kennedy Space Center

Boeing X-37B spacecraft at Vandenberg Air Force Base in California. Photo Credit: Boeing

Archive Photo Credit: Boeing

KENNEDY SPACE CENTER, Fla. — After 718 days on orbit, the U.S. Air Force’s fourth X-37B mission concluded and returned to Earth for an automated landing at Kennedy Space Center’s Shuttle Landing Facility – the first time that the secretive spaceplane has touched down on the historic runway.

The spaceplane heralded its arrival in Florida with twin sonic booms. These were the first in the area by a returning spaceplane since the end of the Shuttle Program in 2011.

“Today marks an incredibly exciting day for the 45th Space Wing as we continue to break barriers,” said Brig. Gen. Wayne Monteith, the 45th SW commander. “Our team has been preparing for this event for several years, and I am extremely proud to see our hard work and dedication culminate in today’s safe and successful landing of the X-37B.”

The U.S. Air Force also posted about the X-37B touching down at around 8:00 a.m. EDT (12:00 GMT) at the SLF after spending some 718 days in orbit.

Amateur astronomers frequently tracked the spaceplane’s movements and orbital changes. On Feb. 8, 2017, it was noted on the Visual Satellite Observer that the spacecraft was a no-show on its expected pass over Bari, Italy. This prompted some to inaccurately speculate that the craft was maneuvering for a landing.

Five days later, it was noted on Federal Aviation Administration’s website that a temporary flight restriction around the Shuttle Landing Facility was in place. However, months passed and the X-37B was still a no-show.

The mission, called Orbital Test Vehicle 4 (OTV-4), was launched on May 20, 2015, atop a United Launch Alliance Atlas V 501 rocket from nearby Cape Canaveral Air Force Station’s Space Launch Complex 41 (SLC-41). It was the second launch of the second X-37B that has been constructed so far. It also was the first flight of one of these spacecraft to be designated under the Air Force Space Command (AFSPC – in the case of this mission, AFSPC-5).

As James Dean at Florida Today noted in his landing article, the Secure World Foundation has stated that there’s virtually “zero” probability the X-37B could be used as a weapons platform to attack targets on the ground.

One of the few experiments that were publicly announced included a test of Aerojet Rocketdyne’s Hall-effect thruster, which is part of the Advanced Extremely High Frequency (AEHF) communications satellite program. Additionally, a NASA investigation called Materials Exposure and Technology Innovation in Space (METIS) tested more than 100 materials.

X-37B afspc5

The X-37B spacecraft launched on May 20, 2015, atop a United Launch Alliance Atlas V 501 rocket from Cape Canaveral Air Force Station’s Space Launch Complex 41 in Florida. Photo Credit: Michael Deep / SpaceFlight Insider

METIS is similar to NASA’s Materials on International Space Station Experiment, also called MISSE, which has seen more than 4,000 material samples tested at the space station.

The X-37B is a reusable spaceplane developed by Boeing. It was a NASA project when it began in 1999, but in 2004 it was transferred to the U.S. Department of Defense. In 2006, a version of the vehicle called the X-37A was used in drop glide tests.

After those were deemed successful, the U.S. Air Force decided to develop a modified version – the X-37B – that would be used for its Orbital Test Vehicle program.

The 11,000-pound (4,990-kilogram) spaceplane measures about 29 feet (8.8 meters) long and has a small cargo bay the size of a pickup truck bed. It’s wingspan measures approximately 15 feet (4.5 meters). It is powered by gallium arsenide solar cells with lithium-ion batteries. Additionally, it has a single maneuvering engine that burns hydrazine and nitrogen tetroxide.

While the spaceplane looks like a mini-Space Shuttle, its thermal protection system is different from the Space Shuttle’s silica tiles. However, exactly what they are made of, as well as a number of other things about the spacecraft, remains secret.

The U.S. Air Force states: “The X-37B Orbital Test Vehicle, or OTV, is an experimental test program to demonstrate technologies for a reliable, reusable, unmanned space test platform for the U.S. Air Force. The primary objectives of the X-37B are twofold: reusable spacecraft technologies for America’s future in space and operating experiments which can be returned to, and examined, on Earth.”

The first flight, OTV-1, launched on April 22, 2010, from SLC-41, also atop an Atlas V 501. It landed 224 days later on Dec. 3, 2010, at Vandenberg Air Force Base in California.

The second mission, OTV-2, launched from SLC-41 just a few months later on March 5, 2011. It spent 468 days in orbit before landing also landing at Vandenberg.

OTV-3 was the first reuse of an X-37B (the same vehicle carried out the OTV-1 mission). It launched on Dec. 11, 2012, from SLC-41 and landed 674 days later on Oct. 17, 2014, at Vandenberg.

All total, the spacecraft have racked up some 2,085 days on orbit during their four missions.

“The hard work of the X-37B OTV team and the 45th Space Wing successfully demonstrated the flexibility and resolve necessary to continue the nation’s advancement in space,” said Randy Walden, the director of the Air Force Rapid Capabilities Office. “The ability to land, refurbish, and launch from the same location further enhances the OTV’s ability to rapidly integrate and qualify new space technologies.”

The U.S. Air Force has stated that it is currently planning on conducting the next flight of one of the spacecraft sometime “later in 2017”. Since 2014, both vehicles have been housed and serviced in Orbiter Processing Facilities 1 and 2, two of the three the former Space Shuttle hangars, at Kennedy Space Center (the third OPF is used by Boeing to prepare its CST-100 Starliner spacecraft for its first flight, currently slated for late 2018 at the earliest).

For their part, the U.S. Air Force noted that the spacecraft has become a source of pride for not just them but the nation.

“The landing of OTV-4 marks another success for the X-37B program and the nation,” said Lt. Col. Ron Fehlen, X-37B program manager via a press release. “This mission once again set an on-orbit endurance record and marks the vehicle’s first landing in the state of Florida. We are incredibly pleased with the performance of the space vehicle and are excited about the data gathered to support the scientific and space communities. We are extremely proud of the dedication and hard work by the entire team.”

Managed by the Air Force Rapid Capabilities Office, the X-37B is the newest, and according to the U.S. Air Force, the most advanced “re-entry spacecraft” presently in operation. The program has a designated purpose of developing reusable spacecraft technologies, risk reduction experimentation, and the concept of operations studies.

Video courtesy of NASA / U.S. Air Force / Sci News



Derek Richardson has a degree in mass media, with an emphasis in contemporary journalism, from Washburn University in Topeka, Kansas. While at Washburn, he was the managing editor of the student run newspaper, the Washburn Review. He also has a website about human spaceflight called Orbital Velocity. You can find him on twitter @TheSpaceWriter.

Reader Comments

Elaine Cummings

I’m a space fan, and have been since APOLLO. This is special news, for sure. Let’s do it again, and again, OK? Fly, baby, fly!

Can we get some info, or speculation on why the workers are wearing hazmat style suits. Are Hall-effect thrusters the issue?

Bill Simpson

No, both components of the spacecraft fuel are quite toxic if inhaled, even in dilute concentrations. Not something you want to even take a single breath of.

Thank you. Perhaps the camera man in the photo is standing too close. 🙂

Can anyone explain why there is a Space Shuttle in the foreground of this landing, I call this Video total BS!!!!

May 9, 2017

Hi Dick,
There’s a mockup of the space shuttle currently at NASA’s Shuttle Landing Facility (SLF), if memory serves, it used to reside at the old Astronaut Hall of Fame. The video is 100 percent legitimate and scores of people, including SFI staff both saw and heard the X-37B arrive.
Jason Rhian – Editor, SpaceFlight Insider

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